KR100273230B1 - Vertical diffusion furnace for semiconductor process and driving method thereof - Google Patents

Abstract

PURPOSE: A vertical diffusion furnace for semiconductor process and a driving method thereof are provided to improve an elevating process of a boat by forming an economical model of a vertical diffusion furnace. CONSTITUTION: An inner tube(12) is formed with a main body(12c), a gas supply tube(12a), and a gas exhaust tube(12b). The main body(12c) is formed by a choked upper end, an opened lower end, and a constant inner spacer. The gas supply tube(12a) and the gas exhaust tube(12b) are connected with the main body(12c). A boat(11) is used for receiving a multitude of wafer(W). A flange(15) is used for opening and shutting a lower opening portion of the inner tube(12) and supporting the boat(11). An outer tube(13) is used for covering the inner tube(12). A heater block(14) is installed around the outer tube(13). The inner tube(12) is installed between a progressive position and a wafer loading/unloading position. The inner tube(12) is elevated with the boat(11) loaded on the flange(15).

Description

Vertical diffusion furnace for semiconductor process and its operation method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical furnace for semiconductor processes and a method of operating the same, and in particular, problems related to the growth of natural oxide films on the wafer surface due to inflow of air, foreign matters generated by thermal stress, and haze The present invention relates to a vertical diffusion furnace for a semiconductor process and a method of operating the same, which solves a problem of occurrence of precipitates during heat treatment of a BPSG film in connection with a generation problem and a boat descent.

There are several processes to manufacture a semiconductor. Among these processes, there is a diffusion process in which impurity atoms are diffused on the wafer surface to form a P-type or N-type semiconductor portion, and one of the equipments used for the diffusion process is a semiconductor process. It is a vertical diffusion furnace.

The vertical diffusion path for a semiconductor process includes a boat (1) for storing dozens of wafers (w) to be processed up and down as shown in FIG. 1, which is a longitudinal cross-sectional view showing a conventional vertical diffusion path for a conventional process (1). Inner tube (2) having a gas supply pipe (2a) for supplying the process gas and a gas discharge pipe (2b) for discharging the used process gas above the boat (1) 2) is provided, the outer tube 3 of the silicon carbide (SiC) material surrounding the inner tube (2) is provided on the outside of the inner tube (2), the outer tube (3) A heater block 4 is installed to maintain the temperature inside the inner tube 2 at a constant process temperature. The intertube 2 and the outer tube 3 and the heater block 4 are in a fixed state, and only the boat 1 is in a state capable of moving up and down as shown by a solid arrow.

Referring to the operation of the conventional vertical diffusion furnace for a semiconductor process having the structure as described above is as follows.

That is, in the state in which the wafer w to be processed is stored in the boat 1, the boat 1 is moved into the inner tube 2 which is heated to the appropriate process temperature by the heater block 4. After the reaction is performed under a proper time, temperature, and gas atmosphere, the boat 1 is lowered to remove the wafer (w) from which the reaction is completed, and the new wafer (w) is stored to resume the process. .

By the way, in the case of the vertical diffusion path for a semiconductor process having the above structure, there are the following problems with respect to the rising and falling of the boat 1, respectively.

First, when the boat 1 rises, there is a problem that a natural oxide film grows on the surface of the wafer w by reaction with oxygen in the atmosphere before the boat is inserted into the inner tube 2. If the growth of the oxide film can be tolerated according to the type of process, there is no problem, but if it exceeds the acceptable level, a separate device is required to solve this problem. 3 is a longitudinal sectional view showing an example of a conventional vertical diffusion path for solving the problem of oxide film growth as described above.

Here, the vertical diffusion path for the semiconductor process shown in FIG. 2 is configured such that the load lock chamber 5 surrounds the outside of the boat 1 and the inside of the load lock chamber 5 is vacuumed using a pump P. FIG. After the nitrogen gas is supplied to the gas supply pipe 5a of the load lock chamber 5, the boat 1 is inserted into the inner tube 2 in the nitrogen atmosphere, and the pump shown in FIG. Instead of making the inside of the load lock chamber 5 into a vacuum using a gas supply pipe 5a of the load lock chamber 5, a large amount of nitrogen gas is purged to make a nitrogen atmosphere and then an inner tube 2 It is configured to be able to insert the boat (1) into the inside of the) is a device that can be used when there is less need to control the oxide film growth than in FIG. Reference numeral 5b in the drawings is a gas discharge pipe installed in the load lock chamber.

On the other hand, another problem that occurs when the boat (1) in the conventional vertical diffusion path is the problem of foreign matter generation due to heat stress. In other words. When the boat 1 rises, the wafer w suddenly receives heat and expands in volume. At this time, the heat received from the front and back sides of the wafer w is not uniform, which causes heat stress. The vibration of w) causes work or foreign matter to occur.

4 and 5 are graphs and tables showing the relationship between the temperature inside the inner tube 2 and the number of vibrations of the wafer w when the boat 1 is raised in the conventional vertical diffusion path. As shown in FIG. As the temperature inside the inner tube 2 increases, the number of vibrations increases, thereby increasing the amount of vibration.

It should be noted that even when the load lock chamber 5 shown in FIGS. 2 and 3 is employed, the temperature of the wafer w can be prevented from suddenly rising when the boat 1 is raised. It is not possible to solve the problem of foreign matters caused by heat stress. Haze is a problem caused by various complex external factors when another boat 1 rises, which is a problem when the boat 1 rises.

On the other hand, in the process of heat-treating the BPSG film formed on the wafer (w) after the end of the process, there is a problem that precipitates are generated on the wafer (w) due to the influence of outside air and temperature introduced when the boat (1) descends. It can be regarded as a problem caused by the fall of 1).

As described above, the vertical diffusion path for a conventional semiconductor process shown in FIG. 1 is a problem associated with the rise of a boat, and the problem of oxide growth due to inflow of outside air, foreign matter generation due to heat stress, and complex external factors. There is a problem with haze generation, and the problem related to the descent of the boat has a problem that precipitates are generated during the heat treatment of the BPSG film due to the action of the outside air during the descent of the boat.

Some of these problems can be solved by operating the load lock chamber as shown in FIG. 2 and FIG. 3, but the cost of operating the load lock chamber separately and additional foreign matters by operating the load lock chamber. The problem that the generation of the process and the process time is long, and that the generation of foreign matter due to thermal stress can not solve the problem even in the case of using the load lock chamber was required a more excellent and economical device.

In Figures 1 to 3, "6" is a flange.

Accordingly, an object of the present invention created under such an environment is to provide a vertical diffusion path for a semiconductor process and a method of operating the same, which can solve all of the above problems associated with raising and lowering a boat.

1 is a longitudinal sectional view showing a conventional vertical diffusion path for a conventional semiconductor process.

2 is a longitudinal sectional view showing another example of a vertical diffusion path for a conventional semiconductor process.

3 is a longitudinal sectional view showing still another example of a vertical diffusion path for a conventional semiconductor process.

4 is a graph showing the relationship between the temperature inside the inner tube in the vertical diffusion furnace and the frequency of wafer vibration when the boat is raised.

5 is a table showing the relationship between the temperature inside the inner tube and the number of wafer vibrations when the boat is raised in the conventional vertical diffusion path.

6 is a longitudinal sectional view showing a structure of a vertical diffusion path for a semiconductor process according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

11: boat 12: inner tube

12a: gas supply pipe 12b: gas discharge pipe

12c: main body 13: outer tube

14: heater block 15: flange

In order to achieve the object of the present invention as described above, the upper end is blocked, the lower end is open and the gas supply pipe and the gas is integrally installed in the main body and the main body is installed so as to be movable on the upper side of the boat with a constant internal space An inner tube including an discharge pipe; A boat in which the plurality of wafers are accommodated; A flange for opening and closing the bottom opening of the inner tube and supporting the boat; An outer tube covering the inner tube; And a heater block disposed around the outer tube, wherein the inner tube includes a process progress position inserted into the outer tube on which the boat is seated and a wafer storage / drawn from the outer tube. There is provided a vertical diffusion path for a semiconductor process, characterized in that it can be installed in a liftable manner with a boat seated on a flange between take-off positions.

In addition, in order to achieve the object of the present invention, the top is blocked and the bottom is open and has a certain internal space, including a gas supply pipe and a gas discharge pipe which is installed on the body and the body is installed so as to be able to move to the upper side of the boat. An inner tube configured; A boat in which the plurality of wafers are accommodated; A flange for opening and closing the bottom opening of the inner tube and supporting the boat; An outer tube covering the inner tube; And a heater block installed around the outer tube; accommodating a plurality of wafers in a boat located outside the inner tube while the inner tube is inserted into the outer tube in the vertical diffusion path for the semiconductor process; ; Lowering the inner tube positioned inside the outer tube to cover the wafer and the boat so that the bottom opening of the inner tube is closed by the flange; Maintaining an inner space of the inner tube closed by the flange in an atmosphere in which an oxide film is difficult to form on a wafer; Integrally raising the inner tube, the boat and the flange so that the inner tube is inserted into the outer tube; Performing a diffusion process; Integrally lowering the inner tube, the boat and the flange after the diffusion process is completed; Raising the inner tube to be inserted into the outer tube while the boat and the flange are stopped in the lowered position; A method of operating a vertical diffusion path for a semiconductor process, comprising the steps of: extracting a wafer from a boat.

Hereinafter, a vertical diffusion path for a semiconductor process according to the present invention will be described according to the embodiment shown in the accompanying drawings.

FIG. 6 is a longitudinal sectional view showing the structure of a vertical diffusion path for a semiconductor process according to an embodiment of the present invention. As shown in FIG. 6, the vertical diffusion path for a semiconductor process according to the present invention is compared with a conventional boat. (11) and the seated flange (15) Of course, the inner tube 12 is installed to be able to lift the main difference, the boat (11) and the inner tube (12) and the outer tube (13) and the heater block (14) It is the same as the conventional one comprised.

That is, the inner tube 12 is installed to be elevated between the process progress position inserted into the outer tube 11 and the wafer storage / takeout position drawn out of the outer tube 11. In addition, the inner tube 12 is installed so that the lifting operation is made in conjunction with the lifting operation of the flange 15.

In the drawings, reference numeral 12c denotes a main body of the intertube, 12a a gas supply pipe, and 12b a gas discharge pipe.

By allowing the inner tube 12 fixed inside the outer butt 13 to be moved up and down, a vertical diffusion furnace for a semiconductor process according to the present invention can be used to meet various requirements of the process. The operation of will be described in detail.

In order to proceed with the process using the vertical diffusion path for the semiconductor process according to the present invention, first, the boat 11 is in a stationary state and the inner tube 12 is positioned inside the outer tube 13.

In this state, the wafers 11 to be processed are accommodated in the boat 11, and then the inner tube 12 descends from the outer tube 13 fixed at a predetermined position so that the boats 11 are accommodated in the boat 11. In addition, the lower end opening of the inner tube 12 is closed by the flange 15 so that the wafer w located in the inner space of the inner tube 12 is kept blocked from the outside air.

When the boat 11 and the inner tube 12 are coupled to each other and the coupling portion is sealed, nitrogen gas or the like is supplied to the gas supply pipe 12a of the main body 12c of the inner tube 12 to suppress natural oxide film growth caused by the outside air during the reaction. Purge to make the atmosphere difficult to form an oxide film, or for more stringent control by connecting a pump (not shown) to the gas discharge pipe (12b) before the injection of nitrogen gas, etc. to draw the outside air inside the inner tube (12) After blowing out, nitrogen gas is blown through the gas supply pipe 12a to create an atmospheric pressure state.

After taking appropriate measures to suppress the oxide film growth according to the degree of process needs, the boat 11, the inner tube 12, and the flange 15 are lifted together in the combined state by the heater block 14 After being coupled to the heated outer tube 13, the process is performed under the conditions of a constant process temperature, process time, and process gas.

On the other hand, as the inner tube 12 and the boat 11 are combined to rise together, the temperature of the conventional wafer w is suddenly changed and foreign matters are generated by thermal stress, which can solve the problem of the wafer (w). This is due to the fact that the inner tube 12 and the gas atmosphere therein act as a thermostat instead of being directly transferred to the heat rapidly, thereby gradually transferring heat.

In addition, the problem of haze generation caused by the complex influence of the external environment is also solved because the wafer w rises in the sealed state inside the inner tube 12 instead of rising in the state exposed to the external environment. .

After the completion of the process after a predetermined time has elapsed, the boat 11 is lowered in a state in which the boat 11 and the inner tube 12 are coupled in the same manner as when the boat 11 is raised, whereby the reaction w is completed. Since the outside air does not come in contact with the wafer 11, the problem that precipitates are generated in the wafer w during the heat treatment of the BPSG film due to the influence of the outside air wet with the wafer w during the descent of the boat 11 can be solved.

Meanwhile, in the vertical diffusion path for semiconductor process according to the present invention as described above, when the inner tube 12 is fixed inside the outer tube 13 as in the prior art, the process is substantially performed in FIG. There will be no difference from the conventional vertical diffusion furnace shown, and thus there will be various problems occurring in the conventional vertical diffusion furnace, and it can be used under very strict conditions without any problems. .

In another case, when it is not necessary to control the growth of the oxide film, the process of making the atmosphere inside the inner tube 12 difficult to oxidize by using nitrogen purge or pump may be omitted. Problems such as foreign substances caused by stress may proceed in a controlled state.

As described above, the vertical diffusion path for semiconductor processing according to the present invention is a natural oxide film growth due to the inflow of outside air, which is a problem associated with the boat rise in the conventional vertical diffusion path for semiconductor processing, foreign matter generation due to thermal stress of the wafer, and The problem of haze generation due to the complex action of the external environment, and the problem of precipitates during heat treatment of the BPSG film due to the external air contacting the wafer, which is a problem related to boat descent, can be solved.

Conventionally, as shown in FIG. 2 and FIG. 3, when the load lock chamber is added and operated, it is possible to solve the problem except for the generation of foreign matter due to heat stress when the boat is raised, but the load lock chamber is operated. It costs a high cost to not be economical and there is a problem such as the generation of new foreign matter by the load lock chamber, but in the present invention solves the problem of foreign matter caused by the heat stress and there is no need to operate a separate load lock chamber There is also an economic effect.

Claims (2)

An inner tube including a gas supply pipe and a gas discharge pipe integrally installed on the main body and a main body installed at the upper side of the boat so as to be movable in the upper and lower sides of the boat with a fixed inner space; A boat in which the plurality of wafers are accommodated; A flange for opening and closing the bottom opening of the inner tube and supporting the boat; An outer tube covering the inner tube; And a heater block disposed around the outer tube, wherein the inner tube includes a process progress position inserted into the outer tube on which the boat is seated and a wafer storage / drawn from the outer tube. A vertical diffusion furnace for a semiconductor process, characterized in that it is installed to be able to be lifted up and down with a boat seated on a flange between ejection positions. An inner tube including a gas supply pipe and a gas discharge pipe integrally installed on the main body and a main body installed at the upper side of the boat so as to be movable in the upper and lower sides of the boat with a fixed inner space; A boat in which the plurality of wafers are accommodated; A flange for opening and closing a lower end of the inner tube and supporting the boat; An outer tube covering the inner tube; And a heater block installed around the outer tube, wherein the plurality of wafers are accommodated in a boat positioned outside the lower side of the intertube while the inner tube is inserted into the outer tube. Wow; Lowering the inner tube positioned inside the outer tube to cover the wafer and the boat so that the bottom opening of the inner tube is closed by the flange; Maintaining an inner space of the inner tube closed by the flange in an atmosphere in which an oxide film is difficult to form on a wafer; Integrally raising the inner tube, the boat and the flange so that the inner tube is inserted into the outer tube; Performing a diffusion process; Integrally lowering the inner tube, the boat and the flange after the diffusion process is completed; Raising the inner tube to be inserted into the outer tube while the boat and the flange are stopped in the lowered position; Extracting the wafer from the boat; the method of operating a vertical diffusion furnace for a semiconductor process.

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